Vessel sealer and divider for large tissue structures

ABSTRACT

An endoscopic bipolar forceps includes a housing having a shaft affixed thereto, the shaft including jaw members at a distal end thereof. The shaft includes jaw members adapted to connect to a source of electrosurgical energy such that the jaw members are capable of conducting energy through tissue held therebetween to effect a tissue seal. The forceps include a drive assembly that moves the jaw members relative to one another from a first position to a second position for manipulating tissue. A movable handle is included that is rotatable about a pivot. A knife assembly is also included having a movable knife rod to operatively engage a knife blade, the knife rod having a first longitudinal section having a first predetermined shape, and a second longitudinal section having a second predetermined shape. The first predetermined shape is different than the second predetermined shape.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.12/233,951 filed on Sep. 19, 2008 (now U.S. Pat. No. 8,734,443) entitled“VESSEL SEALER AND DIVIDER FOR LARGE TISSUE STRUCTURES” by Hixson etal., which claims the benefit of priority to U.S. ProvisionalApplication Ser. No. 60/994,348 entitled “VESSEL SEALER AND DIVIDER FORLARGE TISSUE STRUCTURES” filed on Sep. 19, 2007 by Hixson et al. Both ofthe above applications are incorporated herein by reference.

BACKGROUND

The present disclosure relates to an electrosurgical forceps and moreparticularly, the present disclosure relates to an endoscopic bipolarelectrosurgical forceps for sealing and/or cutting large tissuestructures.

TECHNICAL FIELD

Electrosurgical forceps utilize both mechanical clamping action andelectrical energy to affect hemostasis by heating the tissue and bloodvessels to coagulate, cauterize and/or seal tissue. Many surgicalprocedures require cutting and/or ligating large blood vessels and largetissue structures. Due to the inherent spatial considerations of thesurgical cavity, surgeons often have difficulty suturing vessels orperforming other traditional methods of controlling bleeding, e.g.,clamping and/or tying-off transected blood vessels or tissue. Byutilizing an elongated electrosurgical forceps, a surgeon can eithercauterize, coagulate/desiccate and/or simply reduce or slow bleedingsimply by controlling the intensity, frequency and duration of theelectrosurgical energy applied through the jaw members to the tissue.Most small blood vessels, i.e., in the range below two millimeters indiameter, can often be closed using standard electrosurgical instrumentsand techniques. However, larger vessels can be more difficult to closeusing these standard techniques.

In order to resolve many of the known issues described above and otherissues relevant to cauterization and coagulation, a recently developedtechnology has been developed by Valleylab, Inc. of Boulder, Colo., adivision of Tyco Healthcare LP called vessel or tissue sealing. Theprocess of coagulating vessels is fundamentally different thanelectrosurgical vessel sealing. For the purposes herein, “coagulation”is defined as a process of desiccating tissue wherein the tissue cellsare ruptured and dried. “Vessel sealing” or “tissue sealing” is definedas the process of liquefying the collagen in the tissue so that itreforms into a fused mass with limited demarcation between opposingtissue structures. Coagulation of small vessels is sufficient topermanently close them, while larger vessels and tissue need to besealed to assure permanent closure.

In order to effectively seal larger vessels (or tissue) two predominantmechanical parameters are accurately controlled—the pressure applied tothe vessel (tissue) and the gap distance between the electrodes—both ofwhich are affected by the thickness of the sealed vessel. Moreparticularly, accurate application of pressure is important to opposethe walls of the vessel; to reduce the tissue impedance to a low enoughvalue that allows enough electrosurgical energy through the tissue; toovercome the forces of expansion during tissue heating; and tocontribute to the end tissue thickness which is an indication of a goodseal.

As mentioned above, in order to properly and effectively seal largervessels or tissue, a greater closure force between opposing jaw membersis required. It is known that a large closure force between the jawstypically requires a large moment about the pivot for each jaw. Thispresents a design challenge because the jaw members are typicallyaffixed with pins that are positioned to have small moment arms withrespect to the pivot of each jaw member. A large force, coupled with asmall moment arm, is undesirable because the large forces may shear thepins. As a result, designers compensate for these large closure forcesby either designing instruments with metal pins and/or by designinginstruments that at least partially offload these closure forces toreduce the chances of mechanical failure. As can be appreciated, ifmetal pivot pins are employed, the metal pins should be insulated toavoid the pin acting as an alternate current path between the jawmembers that may prove detrimental to effective sealing.

Increasing the closure forces between electrodes may have otherundesirable effects, e.g., it may cause the opposing electrodes to comeinto close contact with one another that may result in a short circuitand a small closure force may cause pre-mature movement of the tissueduring compression and prior to activation.

As a result thereof, providing an instrument that consistently providesthe appropriate closure force between opposing electrode within apreferred pressure range will enhance the chances of a successful seal.As can be appreciated, relying on a surgeon to manually provide theappropriate closure force within the appropriate range on a consistentbasis would be difficult and the resultant effectiveness and quality ofthe seal may vary. Moreover, the overall success of creating aneffective tissue seal is greatly reliant upon the user's expertise,vision, dexterity, and experience in judging the appropriate closureforce to uniformly, consistently and effectively seal the vessel. Inother words, the success of the seal would greatly depend upon theultimate skill of the surgeon rather than the efficiency of theinstrument.

It has been found that the pressure range for assuring a consistent andeffective seal for large vessels and tissue structures is between about3 kg/cm² to about 16 kg/cm² and, desirably, within a working range of 7kg/cm² to 13 kg/cm². As can be appreciated, manufacturing an instrumentthat is capable of consistently providing a closure pressure withinthese working ranges is quite a design challenge for instrumentmanufacturers.

Various force-actuating assemblies have been developed in the past forproviding the appropriate closure forces to affect vessel sealing. Forexample, one such actuating assembly has been developed by Valleylab,Inc. of Boulder, Colo., a division of Tyco Healthcare LP, for use withValleylab's vessel sealing and dividing instrument for sealing largevessels and tissue structures commonly sold under the trademark LIGASUREATLAS®. The LIGASURE ATLAS® is presently designed to fit through a 10 mmcannula and includes a bi-lateral jaw closure mechanism and is activatedby a foot switch. Co-pending U.S. application Ser. Nos. 10/179,863 and10/116,944 and PCT Application Serial Nos. PCT/US01/01890 andPCT/7201/11340 describe in detail the operating features of the LIGASUREATLAS® and various methods relating thereto. The contents of all ofthese applications are hereby incorporated by reference herein.

Other force-actuating assemblies have also been developed by theValleylab, Inc. of Boulder, Colo., a division of Tyco Healthcare LP, foruse with Valleylab's vessel sealing and dividing instrument for sealinglarge vessels and tissue structures commonly sold under the trademarkLIGASURE 5 mm.™ The LIGASURE 5 mm™ is presently designed to fit througha 5 mm cannula and includes a unilateral jaw closure mechanism and isactivated by a hand switch. Co-pending U.S. application Ser. Nos.10/460,926 and 10/953,757 describe in detail the operating features ofthe LIGASURE 5 mm™ and various methods relating thereto. The entirecontents of both of these applications are hereby incorporated byreference herein.

It would be desirous to develop a vessel sealing instrument thatconsistently produces the required mechanical forces necessary to closethe jaw members about very large tissue structures within a preferredpressure range. It would also be desirous for the instrument to providea mechanical advantage for manipulating the jaw members and clampingtissue, such that, for example, the jaw members can be closed on tissue,easier, quicker and with less user force than previously envisioned toclamp the tissue.

SUMMARY

The forceps includes a housing, a shaft having a longitudinal axisdefined therethrough, a drive assembly and a movable handle. The shaftincludes an end effector assembly having a pair of jaw members attachedto a distal end thereof. The jaw members are movable from a firstposition in spaced relation to one another to at least a second positioncloser to one another. The jaw members are for grasping tissuetherebetween. Each of the jaw members is adapted to connect to anelectrosurgical energy source, thus enabling the jaw members to conductenergy through tissue held between the jaw members to create a tissueseal.

The drive assembly moves the jaw members relative to one another from afirst position wherein the jaw members are disposed in spaced relationrelative to one another to a second position wherein the jaw members arecloser to one another for manipulating tissue. The movable handle isrotatable about a pivot to force a drive flange of the drive assembly tomove the jaw members between the first and second positions. The pivotis located a fixed distance above the longitudinal axis and the driveflange is located generally along the longitudinal axis. This mechanicalarrangement creates level-like mechanical advantage about the pivot tofacilitate closing the jaw members about tissue. The forceps alsoincludes a knife assembly having a generally t-shaped movable knife barthat is dimensioned to operatively engage a corresponding slot definedwithin the housing. The slot guides the movement of the knife bar duringtranslation thereof.

In one embodiment, the knife bar is operatively coupled to a knifeslidingly disposed within the shaft. The forceps further includes afinger actuator operatively coupled to the knife assembly whereinmovement of the finger actuator moves the knife bar which, in turn,moves the knife to cut tissue disposed between the jaw members. Inanother embodiment, the shaft includes a drive sleeve slidingly disposedtherein that operatively connects to the drive assembly for moving thejaw members and the knife assembly includes a cuff at the distal end ofthe knife bar. The cuff is dimensioned to encapsulate and move atop thedrive sleeve upon movement of the knife bar. The forceps may alsoinclude a finger actuator operatively connected to the knife assembly.The finger actuator includes two generally u-shaped flanges that rotateabout a pivot to abut and force the cuff distally which, in turn,results in distal translation of the knife bar.

In yet another embodiment, a spring is included that biases the knifeassembly in a proximal-most orientation. A rotating assembly is alsoincluded and is configured to rotate the jaw members about thelongitudinal axis defined through the shaft. A hand switch may also beincluded within the housing that is adapted to connect to the source ofelectrosurgical energy. The hand switch allows a user to selectivelysupply bipolar energy to the jaw members to affect a tissue seal. Atleast one of the jaw members includes a series of stop members disposedthereon for regulating the distance between the jaw members duringsealing.

The present disclosure also relates to a bipolar forceps that includes ahousing having a shaft affixed thereto. The shaft includes jaw membersattached at a distal end thereof having a longitudinal axis definedtherethrough. The jaw members are adapted to connect to a source ofelectrosurgical energy such that the jaw members are capable ofconducting energy through tissue held therebetween to effect a tissueseal. The forceps also includes a drive assembly that moves the jawmember relative to one another about a pivot from a first positionwherein the jaw members are disposed in spaced relation relative to oneanother to a second position wherein the jaw members are closer to oneanother for manipulating tissue.

A movable handle is included that is rotatable about a pivot to force adrive flange of the drive assembly to move the jaw members between thefirst and second positions. The pivot is located a fixed distance abovethe longitudinal axis and the drive flange is located generally alongthe longitudinal axis. A trigger assembly is included that isoperatively coupled to the housing and operatively coupled to a knifeassembly. The knife assembly includes a drive rod which, upon actuationof the trigger assembly, selectively translates a knife through tissuedisposed between the jaw members. A knife guide may also be includedthat is dimensioned to facilitate alignment and translation of the knifethrough and into a knife channel defined between the jaw members.

In one embodiment, the knife guide includes two engageable halves thatinsulate the jaw members from one another. The knife guide may alsoinclude one or more apertures defined therein that allow the pivot toextend therethrough. The drive assembly may also include a cam pin at adistal end thereof that operatively engages the jaw members and theknife guide may be configured to include one or more slots definedtherein that allow the cam pin to extend therethrough.

In another embodiment, the pivot includes an aperture defined thereinthat allows the knife to extend therethrough. The pivot may include astem and a cap that matingly engage on opposite sides of the shaft tosecure the jaw members during assembly.

In still yet another embodiment, the trigger assembly selectivelytranslates the knife through tissue disposed between the jaw members andthe knife assembly includes a knife carriage having a t-shaped distalend that engages the trigger assembly and a proximal end that engages aknife bar slidingly mounted within the housing. The knife bar mayinclude a cuff at a distal end thereof that defines an aperture locatedtherethrough. The shaft is dimensioned to rotate and slide through theaperture of the cuff.

The drive assembly may further include a cam pin that operativelycouples the distal end of the drive sleeve to the jaw members foractuation thereof. The knife may be dimensioned to include a slotdefined therein that allows the cam pin to extend therethrough.

In embodiments, bipolar forceps include a housing, a shaft affixed tothe housing having jaw members at a distal end thereof, the shaft havinga longitudinal axis defined therethrough. The jaw members are adapted toconnect to a source of electrosurgical energy such that the jaw membersare capable of conducting energy through tissue held therebetween toeffect a tissue seal.

The drive assembly moves the jaw members relative to one another from afirst position wherein the jaw members are disposed in spaced relationrelative to one another to a second position wherein the jaw members arecloser to one another for manipulating tissue. The movable handle isrotatable about a pivot to force a drive flange of the drive assembly tomove the jaw members between the first and second positions. The pivotis located a fixed distance above the longitudinal axis. Moreover, thedrive flange is located generally along the longitudinal axis.

The knife assembly has a movable knife rod to operatively engage a knifeblade, the knife rod having a first longitudinal section having a firstpredetermined shape, and a second longitudinal section having a secondpredetermined shape. In embodiments, the first predetermined shape isdifferent than the second predetermined shape.

In some alternative embodiments, the first longitudinal section of theknife rod has a solid or hollow profile. The first predetermined shapemay have a uniform cross-section along the length of the firstlongitudinal section of the knife rod. The cross-section of the firstlongitudinal section of the knife rod may be in the shape of a circle,square, rectangle, triangle, quadrilateral, or polygon (e.g., pentagon,hexagon, heptagon, octagon, nonagon, or decagon).

In another particular embodiment, the first longitudinal section of theknife rod has three or more peripheral edges rounded along the lengththereof. The first longitudinal section of the knife rod may have one ormore longitudinal flanges along the length thereof, and may include alength of about 2.0 inches to about 5.0 inches along its longitudinalaxis, and a width of about 0.07 inches to about 0.2 inches.

In embodiments, the knife blade is made of a material such as razorblade stainless steel, high carbon steel, high carbon stainless steel,surgical stainless steel, titanium, ceramic materials, zirconium oxide,aluminum, beryllium copper, brass, copper alloys, nickel silver,phosphorous bronze, stainless steel, steel, and combinations thereof.

In embodiments, the knife rod is operatively coupled to a knifeslidingly disposed within the shaft and the forceps further includes afinger actuator operatively coupled to the knife rod wherein movement ofthe finger actuator moves the knife rod which, in turn, moves the knifeto cut tissue disposed between the jaw members. The finger actuator maybe in the shape of a wheel on the distal portion of the housing, a leveron the distal portion of the housing, or a wheel having a first rack, apinion that rotates about a pivot to abut and force the secondlongitudinal section distally which, in turn, results in distaltranslation of the knife.

The bipolar forceps may also include a knife guide dimensioned toprevent tissue from entering the knife channel during activation.Suitable knife guides may include a solid body that insulates the jawmembers from one another.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the subject instrument are described herein withreference to the drawings wherein:

FIG. 1A is a perspective view of a bipolar forceps shown in openconfiguration and including a housing, a shaft, handle assembly, triggerassembly and an end effector assembly according to the presentdisclosure;

FIG. 1B is a perspective view of the bipolar forceps of FIG. 1A shown inclosed configuration;

FIG. 2 is a rear view of the forceps of FIG. 1A;

FIG. 3A is an enlarged, front perspective view of the end effectorassembly of FIG. 1A shown in an open configuration;

FIG. 3B is an enlarged, front perspective view of the end effectorassembly of FIG. 1A shown in a closed configuration;

FIG. 3C is an enlarged, side view of the end effector assembly of FIG.1A shown in open configuration;

FIG. 3D is an enlarge, front view of the end effector assembly of FIG.1A shown in open configuration;

FIG. 3E is a greatly-enlarged, exploded perspective view of the top jawmember;

FIG. 3F is a greatly-enlarged, exploded perspective view of the bottomjaw member;

FIG. 4 is a perspective view of the endoscopic forceps of FIG. 1A withthe internal working components of the forceps exposed;

FIG. 5A is side view of the endoscopic forceps of FIG. 1A with theinternal working components of the forceps exposed;

FIG. 5B is side view of the endoscopic forceps of FIG. 1B with theinternal working components of the forceps exposed;

FIG. 5C is a greatly-enlarged, perspective view of the handle assemblyin open configuration;

FIG. 5D is a greatly-enlarged, perspective view of the handle assemblyin closed configuration;

FIG. 6A is an internal, perspective view of the endoscopic forceps ofFIG. 1B with the internal working components of the forceps exposed andthe trigger shown in an un-actuated position;

FIG. 6B is an internal, perspective view of the endoscopic forceps ofFIG. 1B with the internal working components of the forceps exposed andthe trigger shown in an actuated position;

FIG. 6C is a schematic representation of the electrical configurationfor the trigger assembly;

FIG. 7 is an internal, side view of the endoscopic forceps of FIG. 1Bwith the trigger shown in an actuated position;

FIG. 8A is a side cross-sectional view showing the trigger in anactuated position;

FIG. 8B is an enlarged, side cross-sectional view showing the jawmembers in a spaced apart orientation;

FIG. 8C is an enlarged, side cross-sectional view showing the jawmembers in a closed orientation;

FIG. 9A is side cross-sectional view of the housing showing both thetrigger and the handle un-actuated;

FIG. 9B is side cross-sectional view of the housing showing both thetrigger and the handle actuated;

FIG. 10A is an enlarged, side cross-sectional view showing the endeffector in a closed position and the knife in an unactuated position;

FIG. 10B is an enlarged, side cross-sectional view showing the endeffector in a closed position and the knife in an actuated position;

FIG. 10C is an enlarged, front perspective view of a bottom jaw memberof the end effector assembly showing the knife in an unactuatedposition;

FIG. 10D is an enlarged, front perspective view of the bottom jaw membershowing the knife in an actuated position;

FIG. 11 is an exploded, perspective view of the forceps of FIG. 1A;

FIG. 12 is an enlarged, exploded perspective view of the housing;

FIG. 13 is an enlarged, exploded perspective view of the end effectorassembly and the shaft;

FIG. 14 is a greatly enlarged, exploded perspective view of the endeffector assembly;

FIG. 15A is side view of a knife blade in accordance with the presentdisclosure;

FIG. 15B is a front perspective view of the knife blade of FIG. 15A;

FIG. 16 is a rear perspective view of a knife rod in accordance with thepresent disclosure with a knife blade of FIG. 15A attached thereto;

FIG. 17A is a front cross-sectional view of one possible firstlongitudinal section of the knife rod of FIG. 16.

FIG. 17B is a front cross-sectional view of another envisioned firstlongitudinal section of the knife rod of FIG. 16.

FIG. 17C is a front cross-sectional view of another envisioned firstlongitudinal section of the knife rod of FIG. 16.

FIG. 17D is a front cross-sectional view of another envisioned firstlongitudinal section of the knife rod of FIG. 16.

FIG. 17E is a front cross-sectional view of another envisioned firstlongitudinal section of the knife rod of FIG. 16.

FIG. 17F is a front cross-sectional view of another envisioned firstlongitudinal section of the knife rod of FIG. 16.

FIG. 17G is a front cross-sectional view of another envisioned firstlongitudinal section of the knife rod of FIG. 16.

FIG. 17H is a front cross-sectional view of another envisioned firstlongitudinal section of the knife rod of FIG. 16.

FIG. 17I is a front cross-sectional view of another envisioned firstlongitudinal section of the knife rod of FIG. 16.

FIG. 17J is a front cross-sectional view of another envisioned firstlongitudinal section of the knife rod of FIG. 16.

FIG. 17K is a front cross-sectional view of another envisioned firstlongitudinal section of the knife rod of FIG. 16.

FIG. 17L is a front cross-sectional view of another envisioned firstlongitudinal section of the knife rod of FIG. 16.

FIG. 18 is a schematic side view showing an alternative second knifeactivating mechanism in accordance with the present disclosure.

FIG. 19 is a schematic side view showing an alternative third knifeactivating mechanism in accordance with the present disclosure;

FIG. 20 is a schematic side view showing an alternative fourth knifeactivating mechanism in accordance with the present disclosure; and

FIG. 21 is a schematic side view showing an alternative fifth knifeactivating mechanism in accordance with the present disclosure.

DETAILED DESCRIPTION

Turning now to FIGS. 1A-2, one embodiment of a bipolar forceps 10 isshown for use with various surgical procedures and generally includes ahousing 20, a handle assembly 30, a rotating assembly 80, a triggerassembly 70 and an end effector assembly 100 that mutually cooperate tograsp, seal and divide large tubular vessels and large vascular tissues.Although the majority of the figure drawings depict a bipolar forceps 10for use in connection with endoscopic surgical procedures, the presentdisclosure may be used for more traditional open surgical procedures.For the purposes herein, the forceps 10 is described in terms of anendoscopic instrument, however, it is contemplated that an open versionof the forceps may also include the same or similar operating componentsand features as described below.

Forceps 10 includes a shaft 12 that has a distal end 16 dimensioned tomechanically engage the end effector assembly 100 and a proximal end 14that mechanically engages the housing 20. Details of how the shaft 12connects to the end effector are described in more detail below withrespect to FIGS. 13 and 14. The proximal end 14 of shaft 12 is receivedwithin the housing 20 and the connections relating thereto are alsodescribed in detail below with respect to FIGS. 11 and 12. In thedrawings and in the descriptions that follow, the term “proximal,” as istraditional, will refer to the end of the forceps 10 that is closer tothe user, while the term “distal” will refer to the end that is fartherfrom the user.

As best seen in FIGS. 1A and 2, forceps 10 also includes anelectrosurgical cable 310 that connects the forceps 10 to a source ofelectrosurgical energy, e.g., a generator 500 (shown schematically). Itis contemplated that generators such as those sold by Valleylab—adivision of Tyco Healthcare LP, located in Boulder Colo. may be used asa source of electrosurgical energy, e.g., Ligasure™ Generator, FORCE EZ™Electrosurgical Generator, FORCE FX™ Electrosurgical Generator, FORCE1C™, FORCE 2™ Generator, SurgiStat™ II or other envisioned generatorsthat may perform different or enhanced functions. One such system isdescribed in commonly-owned U.S. Pat. No. 6,033,399 entitled“ELECTROSURGICAL GENERATOR WITH ADAPTIVE POWER CONTROL” the entirecontents of that are hereby incorporated by reference herein. Othersystems have been described in commonly-owned U.S. Pat. No. 6,187,003entitled “BIPOLAR ELECTROSURGICAL INSTRUMENT FOR SEALING VESSELS” theentire contents of which are also incorporated by reference herein.

In one embodiment, the generator 500 includes various safety andperformance features including isolated output, independent activationof accessories. It is envisioned that the electrosurgical generatorincludes Valleylab's Instant Response™ technology features that providesan advanced feedback system to sense changes in tissue 200 times persecond and adjust voltage and current to maintain appropriate power. TheInstant Response™ technology is believed to provide one or more of thefollowing benefits to surgical procedure:

Consistent clinical effect through all tissue types;

Reduced thermal spread and risk of collateral tissue damage;

Less need to “turn up the generator”; and

Designed for the minimally invasive environment.

Cable 310 is internally divided into cable leads 310 a, 310 b and 325 bthat are designed to transmit electrical potentials through theirrespective feed paths through the forceps 10 to the end effectorassembly 100. More particularly, cable feed 325 b connects through theforceps housing 20 and through the rotating assembly to jaw member 120.Lead 310 a connects to one side of the switch 60 and lead 310 c connectsto the opposite side of the switch 60 such that upon activation of theswitch energy is transmitted from lead 310 a to 310 c. Lead 310 c isspliced with lead 310 b that connects through the rotating assembly tojaw member 110 (See FIG. 6C). Details relating to the electricalconnections are explained in more detail below with the discussion ofthe switch 60.

Handle assembly 30 includes a fixed handle 50 and a movable handle 40.Fixed handle 50 is integrally associated with housing 20 and handle 40is movable relative to fixed handle 50 as explained in more detail belowwith respect to the operation of the forceps 10. Fixed handle 50 isoriented approximately 30 degrees relative a longitudinal axis “A-Adefined through shaft 12. Fixed handle 50 may include one or moreergonomic enhancing elements to facilitate handling, e.g., scallops,protuberances, elastomeric material, etc.

Rotating assembly 80 is operatively associated with the housing 20 andis rotatable approximately 180 degrees about a longitudinal axis “A-A”(See FIG. 1A). Details of the rotating assembly 80 are described in moredetail with respect to FIG. 11.

As mentioned above, end effector assembly 100 is attached at the distalend 14 of shaft 12 and includes a pair of opposing jaw members 110 and120. Movable handle 40 of handle assembly 30 is ultimately connected toa drive assembly 130 which, together, mechanically cooperate to impartmovement of the jaw members 110 and 120 from an open position whereinthe jaw members 110 and 120 are disposed in spaced relation relative toone another, to a clamping or closed position wherein the jaw members110 and 120 cooperate to grasp tissue therebetween.

It is envisioned that the forceps 10 may be designed such that it isfully or partially disposable depending upon a particular purpose or toachieve a particular result. For example, end effector assembly 100 maybe selectively and releasably engageable with the distal end 16 of theshaft 12 and/or the proximal end 14 of shaft 12 may be selectively andreleasably engageable with the housing 20 and the handle assembly 30. Ineither of these two instances, the forceps 10 would be considered“partially disposable” or “reposable”, i.e., a new or different endeffector assembly 100 (or end effector assembly 100 and shaft 12)selectively replaces the old end effector assembly 100 as needed. As canbe appreciated, the presently disclosed electrical connections wouldhave to be altered to modify the instrument to a reposable forceps.

Turning now to the more detailed features of the present disclosure asdescribed with respect to FIGS. 1A-21, movable handle 40 includes afinger loop 43 that has an aperture 41 defined therethrough that enablesa user to grasp and move the handle 40 relative to the fixed handle 50.Finger loop 43 is typically ergonomically enhanced and may include oneor more gripping elements (not shown) disposed along the innerperipheral edge of aperture 41 that are designed to facilitate grippingof the movable handle 40 during activation, e.g., a so called “softtouch” material. Gripping elements may include one or moreprotuberances, scallops and/or ribs to enhance gripping.

As best seen in FIGS. 5A and 5B, movable handle 40 is selectivelymovable about a pivot pin 45 a from a first position relative to fixedhandle 50 to a second position in closer proximity to the fixed handle50 which, as explained below, imparts movement of the jaw members 110and 120 relative to one another. The movable handle includes a clevis 46that forms a pair of upper flanges 46 a and 46 b each having an apertureat an upper end thereof for receiving a pivot pin 45 (See FIG. 12)therethrough and mounting the upper end of the handle 40 to the housing20. In turn, pivot pin 45 mounts to respective housing halves 20 a and20 b. Pivot pin 45 is dimensioned to mount within socket 45 a of housinghalf 20 b.

Each upper flange 46 a and 46 b also includes a force-actuating flangeor drive flange 47 a and 47 b (See FIG. 7), respectively, that arealigned along longitudinal axis “A” and that abut the drive assembly 130such that pivotal movement of the handle 40 forces actuating flanges 47a and 47 b against the drive assembly 130 which, in turn, closes the jawmembers 110 and 120 (See FIGS. 5A and 5B). For the purposes herein, 47 aand 47 b that act simultaneously on the drive assembly 130 are referredto as “driving flange 47”. A more detailed explanation of theinter-cooperating components of the handle assembly 30 and the driveassembly 130 is discussed below.

As best shown in FIG. 5C, the lower end of the movable handle 40includes a flange 42 that is typically integrally associated with oroperatively connected to movable handle 40. Flange 42 is typicallyT-shaped and includes a pin-like element 44 that projects laterally ortransversally from a distal end thereof and is configured to engage acorresponding railway 55 disposed within fixed handle 50. Moreparticularly, the pin 44 is configured to ride within a pre-definedchannel 53 disposed within the railway 55 to lock the movable handle 40relative to the fixed handle 50 upon reciprocation thereof. Additionalfeatures with respect to the t-shaped pin 44 are explained below in thedetailed discussion of the operational features of the forceps 10.

Movable handle 40 is designed to provide a distinct mechanical advantageover conventional handle assemblies due to the unique position of thepivot pin 45 (i.e., pivot point) relative to the longitudinal axis “A”of the shaft 12 and the disposition of the driving flange 47 alonglongitudinal axis “A”. In other words, it is envisioned that bypositioning the pivot pin 45 above the driving flange 47, the user gainslever-like mechanical advantage to actuate the jaw members 110 and 120enabling the user to close the jaw members 110 and 120 with lesser forcewhile still generating the required forces necessary to effect a properand effective tissue seal.

As shown best in FIGS. 3A-3F, 13 and 14, the end effector assembly 100includes opposing jaw members 110 and 120 that cooperate to effectivelygrasp tissue for sealing purposes. The end effector assembly 100 isdesigned as a bilateral assembly, i.e., both jaw members 110 and 120pivot relative to one another about a pivot pin 95 disposedtherethrough. The jaw members 110 and 120 are curved to facilitatemanipulation of tissue and to provide better “line of sight” foraccessing organs and large tissue structures.

A reciprocating drive sleeve 134 is slidingly disposed within the shaft12 and is remotely operable by the drive assembly 130 as explained inmore detail below. Drive sleeve 134 includes a bifurcated distal endcomposed of halves 134 a and 134 b, respectively, that define a cavity134′ therebetween for receiving jaw members 110 and 120. Moreparticularly and as best illustrated in FIGS. 13 and 14, jaw members 110and 120 include proximal flanges 113 and 123, respectively, that eachinclude an elongated angled slot 117 and 127, respectively, definedtherethrough. A drive pin 139 (See FIG. 13) mounts jaw members 110 and120 to the end of a sleeve 134 and within cavity 134′ disposed betweenflanges 134 a and 134 b. Cam pin or drive pin 139 mounts throughapertures 139 a and 139 b defined in flanges 134 a and 134 b,respectively, and is reciprocable within slots 16 a′ and 16 b′ disposedat the distal ends 16 a and 16 b of shaft 12 (See FIG. 14). It isenvisioned that slots 16 a′ and 16 b′ may extend into aperture 95′ and95″ to facilitate assembly of pin 139. Pin 139 may be composed of twomechanically interfacing elements that are dimensioned to frictionallyreceive one another to retain pin 139 in place once assembled.Alternatively or in addition, pin 139 may be held in place by one ofseveral known manufacturing techniques including: laser or heat-basedwelding, press-fit mechanical interaction (or other mechanicallyinterlocking geometry, adhesives, chemical bonding, etc. A componentdisposed on the outside of shaft 12 may also be utilized to retain thepin 139 in place once assembled. For example, a heat shrink material,adhesive tape, rubber or other insulating boot or silicone may be usedfor this purpose. It is also envisioned that a varying diameter versionof pin 139 may be utilized to prevent the pin from coming loose onceassembled. It is also envisioned that a cap or stem (not shown)arrangement may be employed for this purpose as well.

Drive sleeve 134, that ultimately connects to the drive assembly 130, isdimensioned to slidingly receive knife drive rod 193, knife 190 andposts 171 a and 171 b of halves 170 a and 170 b of knife guide 170.Drive sleeve 134, in turn, is received within shaft 12. Upon actuationof the drive assembly 130, the drive sleeve 134 reciprocates which, inturn, causes the drive pin 139 to ride within slots 117 and 127 to openand close the jaw members 110 and 120 as desired. The jaw members 110and 120, in turn, pivot about pivot pin 95 disposed through respectivepivot holes 113 a and 123 a disposed within flanges 113 and 123. As canbe appreciated, squeezing handle 40 toward handle 50 pulls drive sleeve134 and drive pin 139 proximally to close the jaw members 110 and 120about tissue grasped therebetween and pushing the sleeve 134 distallyopens the jaw members 110 and 120 for grasping purposes.

Turning back to the details of the jaw member 110 and 120 as best shownin FIGS. 3A-3F, jaw member 110 includes a support base 119 that extendsdistally from flange 113 and that is dimensioned to support aninsulative plate 119′ thereon. Insulative plate 119′, in turn, isconfigured to support an electrically conductive tissue engaging surfaceor sealing plate 112 thereon. It is contemplated that the sealing plate112 may be affixed atop the insulative plate 119′ and support base 119in any known manner in the art, snap-fit, over-molding, stamping,ultrasonically welded, etc. Support base 119 together with theinsulative plate 119′ and electrically conductive tissue engagingsurface 112 are encapsulated by an outer insulative housing 116. Outerhousing 116 includes a cavity 116 a that is dimensioned to securelyengage the electrically conductive sealing surface 112 as well as thesupport base 119 and insulative plate 119′. This may be accomplished bystamping, by overmolding, by overmolding a stamped electricallyconductive sealing plate and/or by overmolding a metal injection moldedseal plate or other more common methods known in the art (i.e., aconductive surface bound to a structural support via an insulatingmaterial). All of these manufacturing techniques produce jaw member 110having an electrically conductive surface 112 that is substantiallysurrounded by an insulating housing or substrate 116.

For example and as shown in FIG. 3E, the electrically conductive sealingplate 112 includes a peripheral flange 112 a that surrounds theperiphery of the sealing plate 112. Flange 112 a is designed to matinglyengage an inner lip 116 b of the outer insulator 116. Again, this may beaccomplished by any of the aforementioned known processes, e.g.,overmolding. It is envisioned that lead 310 b that extends from switch60 (See FIG. 6C) terminates within the outer insulator 116 and isdesigned to electro-mechanically couple to the sealing plate 112 byvirtue of a crimp-like connection 326 a. Insulator 119′, electricallyconductive sealing surface 112 and the outer, non-conductive jaw housing116 are preferably dimensioned to limit and/or reduce many of the knownundesirable effects related to tissue sealing, e.g., flashover, thermalspread and stray current dissipation.

It is envisioned that the electrically conductive sealing surface 112may also include an outer peripheral edge that has a pre-defined radiusand the outer housing 116 meets the electrically conductive sealingsurface 112 along an adjoining edge of the sealing surface 112 in agenerally tangential position. At the interface, the electricallyconductive surface 112 is raised relative to the outer housing 116.These and other envisioned embodiments are discussed in co-pending,commonly assigned Application Serial No. PCT/US01/11412 entitled“ELECTROSURGICAL INSTRUMENT WHICH REDUCES COLLATERAL DAMAGE TO ADJACENTTISSUE” by Johnson et al. and co-pending, commonly assigned ApplicationSerial No. PCT/US01/11411 entitled “ELECTROSURGICAL INSTRUMENT WHICH ISDESIGNED TO REDUCE THE INCIDENCE OF FLASHOVER” by Johnson et al., theentire contents of both of which being hereby incorporated by referenceherein.

The electrically conductive surface or sealing plate 112 and the outerhousing 116, when assembled, form a longitudinally-oriented slot 115 adefined therethrough for reciprocation of the knife blade 190 (See FIG.13). It is envisioned that knife slot 115 a cooperates with acorresponding knife slot 115 b defined in jaw member 120 to facilitatelongitudinal extension of the knife blade 190 along a preferred cuttingplane to effectively and accurately separate the tissue along the formedtissue seal. Together, knife slots 115 a and 115 b form knife channel115 for reciprocation of the knife 190. As best illustrated in FIGS.3A-3F, knife channel 115 runs through the center of the jaw members 110and 120, respectively, such that a blade 190 from the knife assembly 70can cut the tissue grasped between the jaw members 110 and 120 when thejaw members 110 and 120 are in a closed position. As described in moredetail below, handle 30 a includes a passive lockout flange 49′ thatprevents actuation of the knife assembly 70 when the handle 40 is openthus preventing accidental or premature activation of the blade 190through the tissue. In addition, the passive lockout flange 49′ isdimensioned to force the trigger 70 to retract the knife 190 when thehandle 40 is moved to an open position.

As explained above and as illustrated in FIGS. 3F, 8B, 8C, 10C and 10D,the knife channel 115 is formed when the jaw members 110 and 120 areclosed. In other words, the knife channel 115 includes two knife channelhalves—knife slot 115 a disposed in sealing plate 112 of jaw member 110and knife slot 115 b disposed sealing plate 122 of jaw member 120. It isenvisioned that the knife channel 115 may be dimensioned to include somedegree of curvature to cause the knife 190 to move through tissue in acurved fashion. Alternatively, the knife channel 115 may be configuredas a straight slot with no degree of curvature which, in turn, causesthe knife 190 to move through the tissue in a substantially straightfashion. Insulating plate 119′ also forms part of the knife channel 115and includes slot 115 a′ defined therein that extends along insulatingplate 119′ and that aligns in vertical registration with knife slot 115a to facilitate translation of distal end 192 of the knife 190therethrough.

As mentioned above, end effector assembly 100 also includes knife guide170 that is dimensioned to facilitate alignment and translation of theknife 190 through and into the knife channel 115. More particularly,knife guide 170 includes half 170 a and half 170 b that mechanicallyinterface to encapsulate the knife 190 upon assembly (See FIG. 13). Itis envisioned that knife guide 170, once assembled, aligns the knife 190for facile translation through knife channel 115 upon reciprocation of aknife drive rod 193 (FIG. 13). The operation of the drive rod 193 isdescribed below with reference to the operational features of theforceps 10. Each half 170 a and 170 b of the knife guide 170 includesvarious interfaces thereon and apertures defined therein that allowunencumbered movement of the various operating features of the endeffector assembly 100, e.g., pivot 95, drive pin 139 and knife 190. Moreparticularly, halves 170 a and 170 b include apertures 173 a and 173 b,respectively, defined therethrough that allow passage of the pivot 95during assembly. Halves 170 a and 170 b also include laterally-alignedslots 172 a and 172 b defined therein that allow reciprocation of thedrive pin 139 upon opening and closing of the jaw members 110 and 120.One or more guides 327 (FIG. 14) may also be included to guide leads,e.g., lead 325 a, along knife guide 170 and to the electricallyconductive plates, e.g., plate 122. Knife guide halves 170 a and 170 balso include posts 171 a and 171 b that extend proximally into slot 16′upon assembly to engage knife 190. In embodiments, knife guide is asingle molded part assembled around the blade 193 and/or pivot 95. Asbest shown in FIG. 13, knife guide 170 a and 170 b include a shapedflange portion 700. Here, flange portion 700 is of a predetermined shapedesigned to push tissue away from the knife channel 115 during use ofthe device.

Knife channel 115 runs through the center of the jaw members 110 and120, respectively, such that a distal end 192 of the knife 190 can cutthe tissue grasped between the jaw members 110 and 120 when the jawmembers 110 and 120 are in a closed position. More particularly and asdescribed in more detail below with respect to the operation of theforceps 10, the knife 190 can only be advanced through the tissue whenthe jaw members 110 and 120 are closed thus preventing accidental orpremature activation of the knife 190 through the tissue. Passivelockout flange 49′ detailed below prevents unintended translation of theknife 190 while the jaw members 110 and 120 are disposed in an openconfiguration. It is also envisioned that the knife 190 be dimensionedto allow other components to pass therethrough that additionally createsthe benefit of enhancing the overall flexibility of the knife tofacilitate passage through the knife channel 115.

Alternatively, one or both jaw members may also include a safety lockoutto prevent the knife 190 from advancing while the jaw members are in anopen configuration. Various safety lockout configurations are disclosedin commonly owned, co-pending U.S. application Ser. No. 10/962,116entitled “OPEN VESSEL SEALING INSTRUMENT WITH CUTTING MECHANISM ANDDISTAL LOCKOUT” and commonly owned, co-pending U.S. ProvisionalApplication Ser. No. 60/722,177 entitled “IN-LINE VESSEL SEALER ANDDIVIDER”, the entire contents of which are both incorporated byreference herein.

Jaw member 120 includes similar elements to jaw member 110 such as jawhousing 126 that encapsulates a support plate 129, an insulator plate129′ and an electrically conductive sealing surface 122. Likewise, theelectrically conductive surface 122 and the insulator plate 129′, whenassembled, include respective longitudinally-oriented knife slots 115 band 115 b′ defined therethrough for reciprocation of the knife blade190. As mentioned above, when the jaw members 110 and 120 are closedabout tissue, knife slots 115 a and 115 b form a complete knife channel115 to allow longitudinal extension of the knife 190 in a distal fashionto sever tissue along a tissue seal. It is also envisioned that theknife channel 115 may be completely disposed in one of the two jawmembers, e.g., jaw member 120, depending upon a particular purpose. Itis also envisioned that jaw member 120 may be assembled in a similarmanner as described above with respect to jaw member 110. Moreparticularly, the sealing plate 122 may be dimensioned to include anouter peripheral rim 122 a that is dimensioned to mechanically interfacewith an inner lip 126 b of housing 126 to secure the sealing plate 122to the housing 126 with plates 129 and 129′ encapsulated therein.

As best seen in FIG. 3F, jaw member 120 includes a series of stopmembers 90 disposed on the inner facing surface of the electricallyconductive sealing surface 122 to facilitate gripping and manipulationof tissue and to define a gap “G” (FIG. 10B) between opposing jawmembers 110 and 120 during sealing and cutting of tissue. It isenvisioned that the series of stop members 90 may be employed on one orboth jaw members 110 and 120 depending upon a particular purpose or toachieve a desired result. A detailed discussion of these and otherenvisioned stop members 90 as well as various manufacturing andassembling processes for attaching and/or affixing the stop members 90to the electrically conductive sealing surfaces 112, 122 are describedin commonly-assigned, co-pending U.S. Application Serial No.PCT/US01/11413 entitled “VESSEL SEALER AND DIVIDER WITH NON-CONDUCTIVESTOP MEMBERS” by Dycus et al. which is hereby incorporated by referencein its entirety herein.

Jaw member 120 is connected to a second electrical lead 325 b extendingfrom switch 60 (See FIG. 6B) that terminates within the jaw housing 126and is designed to electro-mechanically couple to the sealing plate 122by virtue of a crimp-like connection 326 b. As explained in more detailbelow, leads 310 b and 325 b allow a user to selectively supply bipolarelectrosurgical energy to the jaw members 110 and 120 as needed duringsurgery.

Jaw members 110 and 120 are electrically isolated from one another suchthat electrosurgical energy can be effectively transferred through thetissue to form a tissue seal. For example and as best illustrated inFIGS. 3A-3F, each jaw member 110 and 120 includes a uniquely-designedelectrosurgical cable path that transmits electrosurgical energy throughthe cable leads 310 b and 325 b to the electrically conductive sealingsurfaces 112 and 122, respectively. Cable leads 310 b and 325 b are heldloosely but securely along the cable path to permit rotation of the jawmembers 110 and 120. As can be appreciated, this isolates electricallyconductive sealing surfaces 112 and 122 from the remaining operativecomponents of the end effector assembly 100 and shaft 12. The twoelectrical potentials are isolated from one another by virtue of theinsulative sheathing surrounding the cable leads 310 b and 325 b.

Jaw members 110 and 120 are engaged to the end of rotating shaft 12 bypivot pin 95 such that rotation of the rotating assembly 80correspondingly rotates shaft 12 (along with sleeve 134 and knife 190)which, in turn, rotates end effector assembly 100 (See FIG. 1A). Moreparticularly, the distal end of rotating shaft 12 is bifurcated toinclude ends 16 a and 16 b that define a channel 16′ therein forreceiving jaw members 110 and 120. Pivot pin 95 includes a stem 95 a andcap 95 b arrangement that is dimensioned to engage through aperture 95′and 95″ disposed in ends 16 b and 16 a, respectively. Upon assembly andas best illustrated in FIGS. 13 and 14, the stem 95 a of pivot pin 95extends, in order, through end 16 a of shaft 12, aperture 123 a of jawmember 120, aperture 173 a of half 170 a or knife guide 170, aperture173 b of half 170 b of knife guide 170, aperture 113 a of jaw member 110and end 16 b of shaft 12 to engage cap 95 b. Slots 16 a′ and 16 b′ aredefined within distal ends 16 a and 16 b and are dimensioned to allowreciprocation of drive pin 139 therein. Stem 95 a includes a passthrough hole 96 defined therein that allows passage of the knife 190therethrough for severing tissue while still allowing a large rotationalsurface area for the jaw members during loading.

Turning now to the cooperating components of the housing, FIGS. 5A, 5B,6A, 6B, 11 and 12 show the details of the housing 20 and the componentfeatures thereof, namely, the drive assembly 130, the rotating assembly80, the knife actuating assembly 160, the trigger assembly 70 and thehandles 40 and 50. More particularly, FIGS. 5A and 5B show theabove-identified assemblies and components in an assembled form in thehousing 20 and FIGS. 11 and 12 show an exploded view of each of theabove-identified assemblies and components.

As mentioned above and as best shown in FIGS. 11 and 12, the proximalend of shaft 12 is mechanically engaged to the housing 20. Housing 20 isformed from two (2) housing halves 20 a and 20 b that each include aplurality of interfaces that are dimensioned to mechanically align andengage one another to form housing 20 and enclose the internal workingcomponents of forceps 10. As can be appreciated, fixed handle 50 which,as mentioned above, is integrally associated with housing 20, includeshalves 50 a and 50 b that take the shape of handle 50 upon the assemblyof the housing halves 20 a and 20 b.

It is envisioned that a plurality of additional interfaces (not shown)may disposed at various points around the periphery of housing halves 20a and 20 b for ultrasonic welding purposes, e.g., energydirection/deflection points. It is contemplated that ultrasonic weldingprovides better dimensional stability, strength and joint reliabilitythat other, more traditional, methods. For example, the housing halvesmay be ultrasonically welded utilizing a combination of a primary weldjoint using traditional triangular (or similar) energy directors to forma bonded joint coupled with a secondary hard stop surface (removed fromthe primary joint surface) for preventing over compression of the joint.A tertiary set of alignment pins may be utilized throughout the housinghalves 20 a and 20 b that are configured to both accurately align thehalves 20 a and 20 b during assembly and provide strength and stabilityduring manufacture, handling and transport.

It is also contemplated that housing halves 20 a and 20 b (as well asthe other components described below) may be assembled together in anyfashion known in the art. For example, alignment pins, snap-likeinterfaces, tongue and groove interfaces, locking tabs, adhesive ports,etc. may all be utilized either alone or in combination for assemblypurposes.

As best seen in FIGS. 11 and 12, rotating assembly 80 includes twoC-shaped halves 80 a and 80 b which, when assembled, form the rotatingassembly 80 which, in turn, house the drive assembly 130 and the knifeactuating assembly 160. Half 80 a includes a series of detents/flanges(not shown) that are dimensioned to engage a pair of correspondingsockets or other mechanical interfaces (not shown) disposed withinrotating half 80 b. Half 80 a also includes a tab 84 a (phantomlyillustrated) that together with a corresponding tab 84 b disposed onhalf 80 b cooperate to matingly engage slot 80′ disposed on shaft 12. Ascan be appreciated, this permits selective rotation of the shaft 12about axis “A-A” by manipulating the rotating member 80 in the directionof the arrow “B”, which, in turn, rotates the end effector assembly inthe direction of arrow “C” (See FIG. 1A). The rotating assembly mayinclude one or more mechanical interfaces that essentially lock therotating assembly in a fully counter-clock wise rotational position or afully clockwise rotational position. It is envisioned that this willallow left-handed or right-handed orientations for the end effectorassembly for particular users.

As mentioned above and as best illustrated in FIGS. 5A, 5B, 6A and 6B,the movable handle 40 includes clevis 46 that forms upper flanges 46 aand 46 b that pivot about pins 45 a and 45 b to pull the reciprocatingsleeve 134 along longitudinal axis “A-A” and force driving flanges 47 aand 47 b against the drive assembly 130 which, in turn, closes the jawmembers 110 and 120. The various moving relationships of the flanges 47a and 47 b and the drive assembly 130 are explained in more detail belowwith respect to the operation of the forceps 10. The arrangement of thedriving flanges 47 a and 47 b and the pivot point 45 of the movablehandle 40 provides a distinct mechanical advantage over conventionalhandle assemblies due to the unique position of the pivot pins 45 a and45 b (i.e., pivot point) relative to the longitudinal axis “A-A” of thedriving flanges 47 a and 47 b. In other words, by positioning the pivotpins 29 a and 29 b above the driving flanges 47 a and 47 b, the usergains lever-like mechanical advantage to actuate the jaw members 110 and120. This reduces the overall amount of mechanical force necessary toclose the jaw members 110 and 120 to affect a tissue seal. A similarmechanical arrangement is disclosed in commonly-owned U.S. patentapplication Ser. No. 10/460,926 the entire contents of which areincorporated by reference herein.

Handle 40 also includes a finger loop 43 that defines opening 41 that isdimensioned to facilitate grasping the handle 40. In one embodiment,finger loop 43 includes a rubber insert that enhances the overallergonomic “feel” of the handle member 40. A locking flange 49′ isdisposed on the outer periphery of the handle member 40 above the fingerloop 43. Locking flange 49′ may be designed as a safety lock outmechanism to prevent the trigger assembly 70 from firing when the handlemember 40 is oriented in a non-actuated position, i.e., the jaw members110 and 120 are open. As can be appreciated, this would preventaccidental or premature severing of tissue prior to completion of thetissue seal.

Fixed handle 50 includes halves 50 a and 50 b which, when assembled,form handle 50. Fixed handle 50 includes a channel 51 defined thereinthat is dimensioned to receive flange 42 in a proximal moving mannerwhen movable handle 40 is actuated. The t-shaped pin 44 of handle 40 isdimensioned for facile reception within channel 51 of handle 50. It isenvisioned that flange 42 may be dimensioned to allow a user toselectively, progressively and/or incrementally move jaw members 110 and120 relative to one another from the open to closed positions. Forexample, it is also contemplated that flange 42 may include aratchet-like interface that lockingly engages the movable handle 40 and,therefore, jaw members 110 and 120 at selective, incremental positionsrelative to one another depending upon a particular purpose. Othermechanisms may also be employed to control and/or limit the movement ofhandle 40 relative to handle 50 (and jaw members 110 and 120) such as,e.g., hydraulic, semi-hydraulic, linear actuator(s), gas-assistedmechanisms and/or gearing systems.

As best illustrated in FIGS. 5D and 12, housing halves 20 a and 20 bwhen assembled form an internal cavity 52 that predefines the channel 51within fixed handle 50 adjacent the railway 55 that reciprocatest-shaped pin 44 therein. Once assembled, the railway 55 is seated withincavity 52 in registration with entrance pathway 51 for reciprocation ofthe flange 42. Flange 42 and the housing halves 20 a and 20 b aredesigned to facilitate accurate and consistent reception of the t-shapedpin 44 into railway 55.

During movement of the flange 42 along the entrance to channel 51, thet-shaped pin 44 rides through passage 53 along railway 55 and is forcedinto a catch basin or seat 55′ to lock the handle 40 relative to handle50. When the user releases the handle 40, the catch basin 55′ retainsthe t-shaped pin 44 in a secured position relative to the handle 50 asexplained in further detail below. Railway 55 may be seated on one orpivot elements 55 a that allows the railway 55 to pivot upon receptionof the t-shaped pin 44 therethrough. A spring element 57 biases therailway 55 to return to the original reception position once thet-shaped pin 44 is seated. The railway 55, gain, may pivot in responseto release of the t-shaped pin 44 from catch basin 55′. It is envisionedthat actuation of the handle 40 along with the inter-cooperatingelements of the drive assembly 130 close the jaw members 110 and 120about tissue with a pre-determinable and consistent closure pressure toaffect a tissue seal. As mentioned above, closure pressures for sealinglarge tissue structures preferably fall within the range of about 3kg/cm² to about 16 kg/cm².

When handle 40 is regrasped, the t-shaped pin 44 is forced out of ordisengaged from the catch basin 55′ and moves along an exit pathway torelease handle 40 from channel 51. A spring or other biasing member 57may be employed to facilitate securing the flange 42 within the catchbasin 55′ and also configured to facilitate release of the flange 42from catch basin 55′ upon re-grasping of the handle 40.

As explained in more detail below, once actuated, handle 40 moves in agenerally arcuate fashion towards fixed handle 50 about pivot pins 45 aand 45 b that forces driving assembly 130 proximally which, in turn,pulls reciprocating sleeve 134 in a generally proximal direction toclose jaw members 110 and 120 relative to one another.

As best shown in FIGS. 5A, 5B and 11, the drive assembly 130 mounts atopthe proximal portion of the drive sleeve 134. A pair of retaining ringsor clips 131′ and 131″ (See FIG. 11) cooperate with a corresponding pairof relieved portions 133 a and 133 b disposed on the drive sleeve 134 tomount the drive assembly 130 atop the drive sleeve 134 such thatrelative movement of the drive assembly correspondingly moves the drivesleeve 134. As handle 40 pivots about pivot point 45 and moves relativeto handle 50 and flange 42 is incorporated into channel 51 of fixedhandle 50, the driving flanges 47 a and 47 b, through the mechanicaladvantage of the above-the-center pivot point, force the drive assembly130 proximally against spring 131.

As a result thereof, drive sleeve 134 reciprocates proximally which, inturn, closes the jaw members 110 and 120. It is envisioned that theutilization of an over-the-center pivoting mechanism will enable theuser to selectively compress the coil spring 131 a specific distancewhich, in turn, imparts a specific load on the reciprocating sleeve 134that is converted to a rotational torque about the jaw pivot pin 95. Asa result, a specific closure force can be transmitted to the opposingjaw members 110 and 120.

FIGS. 5A and 5B show the initial actuation of handle 40 towards fixedhandle 50 that causes the pin 44 of flange 42 to move generallyproximally and upwardly along entrance pathway 51. During movement ofthe flange 42 along the entrance pathway 51, respectively, the t-shapedpin 44 rides through passageway 53 along railway 55 as explained above.Once the desired position for the sealing site is determined and the jawmembers 110 and 120 are properly positioned, handle 40 may be compressedfully such that the t-shaped pin 44 of flange 42 seats within catchbasin 55′. Once pin 44 clears an edge or passes a predetermined point inthe passageway 53 at the edge of the catch basin 55′, releasing movementof the handle 40 and flange 42 is redirected into a catch basin 55′.

More particularly, upon a slight reduction in the closing pressure ofhandle 40 against handle 50, the handle 40 returns slightly distallytowards entrance pathway 51 but is re-directed to seat within catchbasin 55′. At this point, the release or return pressure between thehandles 40 and 50 that is attributable and directly proportional to therelease pressure associated with the compression of the drive assembly130 causes the pin 44 of flange 42 to settle or lock within catch basin55′. Handle 40 is now secured in position within fixed handle 50 which,in turn, locks the jaw members 110 and 120 in a closed position againstthe tissue.

As mentioned above, the jaw members 110 and 120 may be opened, closedand rotated to manipulate tissue until sealing is desired. This enablesthe user to position and re-position the forceps 10 prior to activationand sealing. As illustrated in FIG. 1A, the end effector assembly 100 isrotatable about longitudinal axis “A-A” through rotation of the rotatingassembly 80. As explained in more detail below, it is envisioned thatthe unique feed path of the cable leads 325 a and 325 b through therotating assembly 80, along shaft 12 and, ultimately, to the jaw members110 and 120 enables the user to rotate the end effector assembly 100about 180 degrees across the clockwise and counterclockwise directionswithout tangling or causing undue strain on cable leads 325 a and 325 b.As can be appreciated, this facilitates the grasping and manipulation oftissue.

As best shown in FIGS. 5A, 5B, 6A, 9A, 9B, 11 and 12, trigger assembly70 mounts atop movable handle 40 and cooperates with the knife assembly160 to selectively translate knife 190 through a tissue seal. Moreparticularly, the trigger assembly 70 includes a U-shaped fingeractuator 71 having a pair upwardly-extending flanges 71 a and 71 b. Apivot pin 179 extends through a pair of apertures 162 a and 162 b ineach of the flanges 71 a and 71 b, respectively, to mount the triggerassembly 70 to a knife carriage 165 as explained in more detail below.Finger actuator 71 is selectively pivotable within a pre-defined slot 21disposed within housing 20 (See FIG. 6A). More particularly, a pair ofpivots 77 a and 77 b is disposed on either side of the finger actuator71 and are configured to mount between housing halves 20 a and 20 b topivot the finger actuator within slot 21.

The knife assembly 160 includes a reciprocating knife bar 167 thatmounts atop the drive sleeve 134 and between upwardly extending flanges71 a and 71 b. Knife bar 167 includes a t-shaped proximal end 167′ and acuff 137 disposed at the distal end thereof. Cuff 137 is dimensioned toencapsulate drive sleeve 134 when the knife assembly 160 is assembled. Aspring 76 biases the cuff in a proximal-most orientation. Proximal end167′ is dimensioned to mount and slidingly reciprocate within a slot167″ formed by housings 20 a and 20 b at assembly (See FIG. 12). Alocking cap 137 a and a mounting pin 179 secure the cuff 137 to theproximal end 193 b of the knife rod 193 through aperture 197 disposedtherein such that proximal movement to the finger actuator 71 results indistal movement of the knife bar 193. Cuff 137 and cap 137 a also allow360 degrees of rotation of the drive sleeve 134 therethrough.

As mentioned above, a knife carriage 165 mounts to the upwardlyextending flanges 71 a and 71 b of the finger actuator 71. Moreparticularly, the distal end 162 of the knife carriage 165 is t-shapedand includes two laterally extending pins 162 c and 162 d that engageapertures 162 a and 162 b, respectively, in flanges 71 a and 71 b. Theproximal end 161 of the knife carriage 165 includes an aperture 161 adefined therein that mates with a detent 167 a that extendstransversally through knife carriage 165.

As best illustrated in FIGS. 5A-7, when the handle 40 is disposed in aspaced-apart or open configuration relative to handle 50, flange 49′that extends from handle 40 prevents actuation of the trigger assembly70. More particularly, finger actuator 71 is prevented from beingactuated proximally by flange 49′ when the jaw members 110 and 120 areopen. As can be appreciated, this prevents premature actuation of theknife 190 when tissue is not grasped between jaw members 110 and 120.When handle 40 is selectively moved relative to handle 50, a gap 21 isformed between the flange 49′ and the finger actuator 71 (See FIG. 5B).Thus, the user is free to selectively actuate the knife 190 by squeezingthe finger actuator 71 proximally within gap 21.

As best shown in FIGS. 6B, 7 and 8A, once the clearance is provided bymovement of handle 40, proximal movement of the finger actuator 71 aboutpivot 74 results in distal translation of the knife bar 167 which, inturn, results in distal translation of the knife rod 193 and knife 190.More particularly, when finger actuator 71 is squeezed proximally, theU-shaped flanges 71 a and 71 b rotate about pivot 74 to abut cuff 137and essentially throw the knife carriage 165 forward which, in turn,carries the knife bar 167 forward to force the knife rod 193 distally.Slot 167″ is configured to smoothly guide the knife bar 167 distallythrough the forward and return stroke. As shown in FIGS. 10A and 10BC,distal translation of the knife rod 193 translates the knife 190 throughchannel 115 in the jaw members 110 and 120. As mentioned above, theknife rod 193 mounts the knife 190 via one or more mechanicallyinterfacing elements or may be affixed in any known manner in the art. Aslot 197 defined within the knife 190 provides clearance for pin 139 ofthe drive sleeve 134 during reciprocation of the knife 190. Upon releaseof finger actuator 71, spring 76 biases the knife assembly back to aproximal-most position. It is envisioned that the knife bar 167 providesvariable mechanical advantage and linear advantage when triggering theknife 190. In addition, the incorporation of the knife bar 167significantly reduces friction loss and provides smoother mechanicalcutting than previously known methods.

Turning now in detail to the operation of the drive assembly as bestseen in FIGS. 5A, 5B, 11 and 12, drive assembly 130 includesreciprocating sleeve 134, drive housing 135, spring 131, drive rings 135a and 135 b, drive stops 135 c and 135 d and retaining rings 131′ and131″ that all cooperate to form the drive assembly 130. It is envisionedthat stop 135 c may be removed and ring 131″ would perform stop 135 c'sintended function. The proximal end 132 of the reciprocating sleeve 134is positioned within an aperture 135′ defined through the drive housing135 to permit selective reciprocation of the drive sleeve 134therethrough upon actuation of the movable handle 40. The spring 131 isassembled atop the drive housing 135 between a rear stop 135 d and ring135 b such that movement handle 40 about pivot 45 moves the entire driveassembly 130 and sleeve 134 proximally which, in turn, pulls cam pin 139proximally to close the jaw members 110 and 120. Once the jaw members110 and 120 close about tissue, the drive assembly 130 essentiallybottoms out (i.e., further proximal movement of the reciprocating sleeveis prevented) and further movement of handle 40 about pivot 45compresses spring 131 resulting in additional closure force on thetissue. Moreover, spring 131 also tends to bias the jaw members 110 and120 and the movable handle 40 in an open configuration.

Turning back to FIG. 12 that shows the exploded view of the housing 20,rotating assembly 80, trigger assembly 70, movable handle 40 and fixedhandle 50, it is envisioned that all of these various component partsalong with the shaft 12 and the end effector assembly 100 are assembledduring the manufacturing process to form a partially and/or fullydisposable forceps 10. For example and as mentioned above, the shaft 12and/or end effector assembly 100 may be disposable and, therefore,selectively/releasably engageable with the housing 20 and rotatingassembly 80 to form a partially disposable forceps 10 and/or the entireforceps 10 may be disposable after use.

As best seen in FIGS. 5A, 5B and 13, once assembled, spring 131 ispoised for compression atop drive housing 135 upon actuation of themovable handle 40. More particularly, movement of the handle 40 aboutpivot pins 45 a and 45 b reciprocates the flange 42 into fixed handle 50and forces drive assembly 130 to compress spring 131 against the rearstop 135 d to reciprocate the sleeve 134.

As mentioned above, the trigger assembly 70 is initially prevented fromfiring by the locking flange 49′ disposed on movable handle 40 thatabuts against the trigger assembly 70 prior to actuation. It isenvisioned that the opposing jaw members 110 and 120 may be rotated andpartially opened and closed without unlocking the trigger assembly 70which, as can be appreciated, allows the user to grip and manipulate thetissue without premature activation of the knife assembly 160. Asmentioned below, only when the t-shaped pin 44 of flange 42 iscompletely reciprocated within channel 51 of the fixed handle 50 andseated within pre-defined catch basin 55′ will the locking flange 49′allow full activation of the trigger assembly 70. The operating featuresand relative movements of these internal working components of theforceps 10 are shown by phantom representation and directional arrowsand are best illustrated in the various figures.

It is envisioned that the mechanical advantage of the over-the-centerpivot will enable the user to selectively compress the coil spring 131 aspecific distance which, in turn, imparts a specific load on thereciprocating sleeve 134. The reciprocating sleeve's 134 load isconverted to a torque about the jaw pivot 95. As a result, a specificclosure force can be transmitted to the opposing jaw members 110 and120. As mentioned above, the jaw members 110 and 120 may be opened,closed and rotated to manipulate tissue until sealing is desired withoutunlocking the trigger assembly 70. This enables the user to position andre-position the forceps 10 prior to activation and sealing. Moreparticularly, as illustrated in FIG. 1A, the end effector assembly 100is rotatable about longitudinal axis “A-A” through rotation of therotating assembly 80.

Once the desired position for the sealing site is determined and the jawmembers 110 and 120 are properly positioned, handle 40 may be compressedfully such that the t-shaped pin 44 of flange 42 clears a pre-definedrailway edge located atop the railway 55. Once end 44 clears the railwayedge, the end 44 is directed into catch basin 55′ to lock the handle 40relative to handle 50. The release or return pressure between thehandles 40 and 50 that is attributable and directly proportional to therelease pressure associated with the compression of the drive assembly130 causes the end 44 of flange 42 to settle or lock within catch basin55′. Handle 40 is now secured in position within fixed handle 50 which,in turn, locks the jaw members 110 and 120 in a closed position againstthe tissue.

At this point the jaws members 110 and 120 are fully compressed aboutthe tissue. Moreover, the forceps 10 is now ready for selectiveapplication of electrosurgical energy and subsequent separation of thetissue, i.e., as t-shaped end 44 seats within catch basin 55′, lockingflange 49′ moves into a position to permit activation of the triggerassembly 70.

As the t-shaped end 44 of flange 42 seats within catch basin 55′, aproportional axial force on the reciprocating sleeve 134 is maintainedwhich, in turn, maintains a compressive force between opposing jawmembers 110 and 120 against the tissue. It is envisioned that the endeffector assembly 100 and/or the jaw members 110 and 120 may bedimensioned to off-load some of the excessive clamping forces to preventmechanical failure of certain internal operating elements of the endeffector 100.

As can be appreciated, the combination of the mechanical advantage ofthe over-the-center pivot along with the compressive force associatedwith the compression spring 131 facilitate and assure consistent,uniform and accurate closure pressure about the tissue within thedesired working pressure range of about 3 kg/cm² to about 16 kg/cm² and,desirably, about 7 kg/cm² to about 13 kg/cm². By controlling theintensity, frequency and duration of the electrosurgical energy appliedto the tissue, the user can treat tissue, i.e., seal tissue.

As mentioned above, two mechanical factors play an important role indetermining the resulting thickness of the sealed tissue andeffectiveness of the seal, i.e., the pressure applied between opposingjaw members 110 and 120 and the gap distance “G” between the opposingsealing surfaces 112, 122 of the jaw members 110 and 120 during thesealing process. However, thickness of the resulting tissue seal cannotbe adequately controlled by force alone. In other words, too much forceand the two jaw members 110 and 120 would touch and possibly shortresulting in little energy traveling through the tissue thus resultingin a bad tissue seal 450. Too little force and the seal would be toothick.

Applying the correct force is also important for other reasons: tooppose the walls of the vessel; to reduce the tissue impedance to a lowenough value that allows enough current through the tissue; and toovercome the forces of expansion during tissue heating in addition tocontributing towards creating the required end tissue thickness that isan indication of a good seal.

In one embodiment, the electrically conductive sealing surfaces 112 and122 of the jaw members 110 and 120, respectively, are relatively flat toavoid current concentrations at sharp edges and to avoid arcing betweenhigh points. In addition and due to the reaction force of the tissuewhen engaged, jaw members 110 and 120 can be manufactured to resistbending. For example, the jaw members 110 and 120 may be tapered alongthe width thereof that is advantageous for two reasons: 1) the taperwill apply constant pressure for a constant tissue thickness atparallel; 2) the thicker proximal portion of the jaw members 110 and 120will resist bending due to the reaction force of the tissue.

As mentioned above, at least one jaw member, e.g., 120, may include oneor more stop members 90 that limit the movement of the two opposing jawmembers 110 and 120 relative to one another. In one embodiment, the stopmembers 90 extend from the sealing surface 122 a predetermined distanceaccording to the specific material properties (e.g., compressivestrength, thermal expansion, etc.) to yield a consistent and accurategap distance “G” during sealing (FIG. 10B). It is envisioned for the gapdistance between opposing sealing surfaces 112 and 122 during sealingranges from about 0.001 inches to about 0.006 inches and, desirably,between about 0.002 and about 0.005 inches. In one embodiment, thenon-conductive stop members 90 are molded onto the jaw members 110 and120 (e.g., overmolding, injection molding, etc.), stamped onto the jawmembers 110 and 120 or deposited (e.g., deposition) onto the jaw members110 and 120. For example, one technique involves thermally spraying aceramic material onto the surface of the jaw member 110 and 120 to formthe stop members 90. Several thermal spraying techniques arecontemplated that involve depositing a broad range of heat resistant andinsulative materials on various surfaces to create stop members 90 forcontrolling the gap distance between electrically conductive surfaces112 and 122.

As energy is being selectively transferred to the end effector assembly100, across the jaw members 110 and 120 and through the tissue, a tissueseal forms isolating two tissue halves. At this point and with otherknown vessel sealing instruments, the user may remove and replace theforceps 10 with a cutting instrument (not shown) to divide the tissuehalves along the tissue seal. As can be appreciated, this is both timeconsuming and tedious and may result in inaccurate tissue divisionacross the tissue seal due to misalignment or misplacement of thecutting instrument along the ideal tissue cutting plane.

As explained in detail above, the present disclosure incorporates knifeassembly 160 which, when activated via the trigger assembly 70,progressively and selectively divides the tissue along an ideal tissueplane in a precise manner to effectively and reliably divide the tissueinto two sealed halves. The knife assembly 160 allows the user toquickly separate the tissue immediately after sealing withoutsubstituting a cutting instrument through a cannula or trocar port. Ascan be appreciated, accurate sealing and dividing of tissue isaccomplished with the same forceps 10.

It is envisioned that knife blade 190 may also be coupled to the same oran alternative electrosurgical energy source to facilitate separation ofthe tissue along the tissue seal. Moreover, it is envisioned that theangle of the trip of the knife blade 190 may be dimensioned to providemore or less aggressive cutting angles depending upon a particularpurpose. For example, the knife blade 190 may be positioned at an anglethat reduces “tissue wisps” associated with cutting. Moreover, the knifeblade 190 may be designed having different blade geometries such asserrated, notched, perforated, hollow, concave, convex etc. dependingupon a particular purpose or to achieve a particular result. It isenvisioned that the knife assembly 160 generally cuts in a progressive,uni-directional fashion (i.e., distally).

Once the tissue is divided into tissue halves, the jaw members 110 and120 may be opened by re-grasping the handle 40 as explained below.Re-initiation or re-grasping of the handle 40 again moves t-shaped pin44 of flange 42 generally proximally.

As best shown in FIG. 13, the proximal portions of the jaw members 110and 120 and the distal end 16 of shaft 12 may be covered by a resilientor flexible insulating material 185 to reduce stray currentconcentrations during electrosurgical activation. An insulating boot(not shown) may also be positioned atop the proximal portions of the jawmembers 110 and 120 to further reduce current concentrations and straycurrents from damaging adjacent tissue. Details relating to oneenvisioned insulating boot 220 are described with respect tocommonly-owned U.S. Provisional Application Ser. No. 60/722,213 entitled“INSULATING BOOT FOR ELECTROSURGICAL FORCEPS”, the entire contents ofwhich being incorporated by reference herein.

Switch 60 is ergonomically dimensioned and conforms to the outer shapeof housing 20 (once assembled). Switch 60 is designed toelectromechanically cooperate with a flex circuit 400 (See FIG. 6C) toallow a user to selectively activate the jaw members 110 and 120. It iscontemplated that a flex circuit design facilitates manufacturing due tothe circuit unique ability to conform as needed into tightly spacedareas. It is also envisioned that the switch 60 permits the user toselectively activate the forceps 10 in a variety of differentorientations, i.e., multi-oriented activation or toggle-like activation.As can be appreciated, this simplifies activation. It is envisioned thatswitch 60 may also be designed as a so called “dome switch” that alsoprovides tactile feedback to the user when activated.

When switch 60 is depressed, trigger lead 310 b carries the firstelectrical potential to jaw member 110 thus completing a bipolarcircuit. More particularly, when switch 60 is depressed and flex circuit400 is activated, the generator recognizes a voltage drop across leads310 a and 310 c that initiates activation of the generator to supply afirst electrical potential to jaw member 110 and a second electricalpotential to jaw member 120. Switch 60 acts as a control circuit and isprotected or removed from the actual current loop that supplieselectrical energy to the jaw members 110 and 120. This reduces thechances of electrical failure of the switch 60 due to high current loadsduring activation. A footswitch (not shown) that may also be utilizedwith the forceps 10, also operates in a similar manner, i.e., uponactivation of the footswitch, the generator recognizes a voltage dropacross the input and output leads of the footswitch which, in turn,signals the generator to initiate electrosurgical activation of the jawmembers 110 and 120.

It is envisioned that a safety switch or circuit (not shown) may beemployed such that the switch cannot fire unless the jaw members 110 and120 are closed and/or unless the jaw members 110 and 120 have tissueheld therebetween.

In the latter instance, a sensor (not shown) may be employed todetermine if tissue is held therebetween. In addition, other sensormechanisms may be employed that determine pre-surgical, concurrentsurgical (i.e., during surgery) and/or post surgical conditions. Thesensor mechanisms may also be utilized with a closed-loop feedbacksystem coupled to the electrosurgical generator to regulate theelectrosurgical energy based upon one or more pre-surgical, concurrentsurgical or post surgical conditions. Various sensor mechanisms andfeedback systems are described in commonly-owned, co-pending U.S. patentapplication Ser. No. 10/427,832 entitled “METHOD AND SYSTEM FORCONTROLLING OUTPUT OF RF MEDICAL GENERATOR” filed on May 1, 2003 theentire contents of which are hereby incorporated by reference herein.

The jaw members 110 and 120 are electrically isolated from one anothersuch that electrosurgical energy can be effectively transferred throughthe tissue to form seal. The cable leads 310 b and 325 b are heldloosely but securely along the cable path to permit rotation of the jawmembers 110 and 120 about longitudinal axis “A” (See FIG. 1A). Moreparticularly, cable leads 310 b and 325 b are fed through respectivehalves 80 a and 80 b of the rotating assembly 80 in such a manner toallow rotation of the shaft 12 (via rotation of the rotating assembly80) in the clockwise or counterclockwise direction without undulytangling or twisting the cable leads 310 b and 325 b. The presentlydisclosed cable lead feed path is envisioned to allow rotation of therotation assembly approximately 180 degrees in either direction.

From the foregoing and with reference to the various figure drawings,those skilled in the art will appreciate that certain modifications canalso be made to the present disclosure without departing from the scopeof the same. For example, it may be preferable to add other features tothe forceps 10, e.g., an articulating assembly to axially displace theend effector assembly 100 relative to the elongated shaft 12.

It is also contemplated that the forceps 10 (and/or the electrosurgicalgenerator used in connection with the forceps 10) may include a sensoror feedback mechanism (not shown) that automatically selects theappropriate amount of electrosurgical energy to effectively seal theparticularly-sized tissue grasped between the jaw members 110 and 120.The sensor or feedback mechanism may also measure the impedance acrossthe tissue during sealing and provide an indicator (visual and/oraudible) that an effective seal has been created between the jaw members110 and 120. Examples of such sensor systems are described incommonly-owned U.S. patent application Ser. No. 10/427,832 entitled“METHOD AND SYSTEM FOR CONTROLLING OUTPUT OF RF MEDICAL GENERATOR” filedon May 1, 2003 the entire contents of which are hereby incorporated byreference herein.

Moreover, it is contemplated that the trigger assembly 70 may includeother types of recoil mechanism that are designed to accomplish the samepurpose, e.g., gas-actuated recoil, electrically-actuated recoil (i.e.,solenoid), etc. It is also envisioned that the forceps 10 may be used tocut tissue without sealing. Alternatively, the knife assembly 70 may becoupled to the same or alternate electrosurgical energy source tofacilitate cutting of the tissue.

It is envisioned that the outer surface of the end effector assembly 100may include a nickel-based material, coating, stamping, metal injectionmolding that is designed to reduce adhesion between the jaw members 110and 120 with the surrounding tissue during activation and sealing.Moreover, it is also contemplated that the conductive surfaces 112 and122 of the jaw members 110 and 120 may be manufactured from one (or acombination of one or more) of the following materials: nickel-chrome,chromium nitride, MedCoat 2000 manufactured by The ElectrolizingCorporation of OHIO, inconel 600 and tin-nickel. The tissue conductivesurfaces 112 and 122 may also be coated with one or more of the abovematerials to achieve the same result, i.e., a “non-stick surface”. Ascan be appreciated, reducing the amount that the tissue “sticks” duringsealing improves the overall efficacy of the instrument.

One particular class of materials disclosed herein has demonstratedsuperior non-stick properties and, in some instances, superior sealquality. For example, nitride coatings that include, but not are notlimited to: TiN, ZrN, TiAlN, and CrN are preferred materials used fornon-stick purposes. CrN has been found to be particularly useful fornon-stick purposes due to its overall surface properties and optimalperformance. Other classes of materials have also been found to reducingoverall sticking. For example, high nickel/chrome alloys with a Ni/Crratio of approximately 5:1 have been found to significantly reducesticking in bipolar instrumentation. One particularly useful non-stickmaterial in this class is Inconel 600. Bipolar instrumentation havingsealing surfaces 112 and 122 made from or coated with Ni200, Ni201(˜100% Ni) also showed improved non-stick performance over typicalbipolar stainless steel electrodes.

As can be appreciated, locating the switch 60 on the forceps 10 has manyadvantages. For example, the switch 60 reduces the amount of electricalcable in the operating room and eliminates the possibility of activatingthe wrong instrument during a surgical procedure due to “line-of-sight”activation. Moreover, it is also envisioned that the switch 60 may beconfigured such that it is mechanically or electro-mechanicallydecommissioned during trigger activation to eliminate unintentionallyactivating the device during the cutting process. It is also envisionedthat the switch 60 may be disposed on another part of the forceps 10,e.g., the fixed handle 50, rotating assembly 80, housing 20, etc.

It is also envisioned that the forceps 10 may be equipped with anautomatic, electro-mechanical release mechanism (not shown) thatreleases the tissue once an end seal is determined (i.e., end-tonesignal from the generator). For example, an electromechanical interfacemay be configured to automatically release the t-shaped pin 44 fromcatch basin 55 upon an end tone condition.

It is also contemplated that the forceps 10 may be dimensioned toinclude a trigger assembly 70 that operates in lieu of the switchassembly 60 to activate the forceps to seal tissue while also advancingthe knife 190 to divide the tissue across the seal. For example, thetrigger assembly 70 could be configured to have two stages: a first orinitial stroke stage that activates the generator to selectively sealtissue; and a second or subsequent stage that advances the knife throughthe tissue. Alternatively, another embodiment may include a triggerassembly that simultaneously activates the jaw members 110 and 120 toseal tissue and advances the knife 190 through the tissue duringactivation.

It is also envisioned that the rotating assembly 80 may be equipped withone or more mechanical interfaces that are rotatable with or within therotating assembly 80 and that are configured to produce tactile and/oraudible feedback to the user during rotation. The tactile and/or audiblefeedback (i.e., a “click”) may be configured to correspond to aparticular degree of rotation of the end effector assembly 100 about theaxis “A”. It is also contemplated that one or more types of visualindicia may also be employed with the rotating assembly 80 to correspondto the amount or degree of rotation of the end effector assembly 100 andmay be designed correspond to or relate to the audible and/or tactilefeedback depending upon a particular purpose.

Another envisioned version of the forceps 10 may include a telescopingshaft that allows the user to selectively regulate the length of theinstrument for particular surgical purposes. For example, it isenvisioned that the shaft may include two slidingly reciprocatable andextendible elements that upon exertion (i.e., pulling, twisting, or byvirtue of a mechanical lever on the handle) either lengthen or shortenthe size of the elongated shaft 12 depending upon a particular surgicalpurpose.

Moreover, it is also contemplated that the diameter of shaft 12 may beselectively expandable depending upon a particular surgical purpose orto provide rigidity of the forceps 10 inside the surgical cavity or toenhance the sealing effect of the shaft through a trocar. Moreparticularly, it is contemplated that the shaft 12 may be configured toexpand upon exertion (i.e., twisting or rotating one element insideanother (iris-like), sliding a mechanical lever, an inflatable system, amechanically expanding system or other types of known expansionsystems). As a result, the surgeon can selectively expand the outerdiameter of the shaft 12 to enhance the rigidity of the shaft 12 withina trocar and/or enhance the sealing effect of the shaft 12 within thetrocar to reduce the possibility of pressure leakage from surgicalcavity during use. Moreover, a single forceps may be selectivelyadaptable to work with differently-sized trocars and/or cannulas thatmay prove advantageous for particular operations and other surgicalprocedures.

It is also contemplated that the forceps 10 may be configured such thathandle 50 is selectively replaceable or selectively positionabledepending upon user preference. For example, handle 50 may beselectively detached and replaced with another handle 50 that is ofdifferent dimension (i.e., size, weight, angle, orientation to user'shand, etc.) that facilitates handling during surgical procedures.Alternatively, handle 50 may be selectively positionable relative to thehousing 20 (i.e., the angle of the handle to the housing is adjustable)to facilitate handling and use during particular surgical procedures orfor user comfort.

It is also envisioned that the forceps may be configure to include avisual indicator (which cooperates with the “end tone” indicator on thegenerator) to provide visual confirmation of a successful seal (e.g., agreen LED indicator). The visual indicator (not shown) may be employedon or in connection with the end effector assembly 100 or shaft 12 thatis in line-of-site of the surgeon during use. The visual indicator mayalso be designed to warn the user of a mis-seal condition or a re-graspcondition (e.g., a red LED indicator). Alternatively, the visualindicator may also be configured to provide progressive feedback of theformation of the seal during the sealing process. For example, a seriesof LEDs may be employed on the end effector assembly 100 (or shaft 12)that progressively illuminate through the sealing process to providevisual feedback to the user regarding the status of the seal. Moreover,it is envisioned that one or both jaw members may include visualmarkings that indicate the end of a seal and/or the length of the sealcut.

It is also envisioned that the guide element 170 (See FIG. 14) may beconfigured to not only guide the knife 190 into the knife channel 115disposed between the jaw members 110 and 120, but may also bedimensioned to precisely space the jaw members 110 and 120 relative toone another about the pivot 95. Moreover, the guide element 170 may beconfigured to include one or more grooves of tracks (not shown) to guidethe electrical connections or wires 310 b and 325 b through the endeffector assembly 100. The guide element 170 may also be configured tolimit the distal movement of the drive rod 193 for the knife 190 which,in turn, limits the overall travel of the knife 190 through the knifechannel 115.

It is also contemplated that the stem 95 a of the pivot pin 95 mayinclude a stepped diameter that securely compresses the jaw members 110and 120 together when mechanically secured with the cap 95 b. Moreover,the pivot may be dimensioned to include a pass through or aperture 96that allows translation of the knife therethrough. The two-piece pivot95 including stem 95 a and cap 95 b may be assembled during themanufacturing process by any one of several known manufacturingtechniques including: laser or heat-based welding, press-fit mechanicalinteraction (or other mechanically interlocking geometry, adhesives,chemical bonding, etc.

It is also envisioned that the shaft may be dimensioned to enhancevisibility and/or non-symmetric depending upon a particular purpose. Forexample, it is contemplated that the shaft may be generally oval indimension thereby providing uni-directional strength in one dimensionversus another and maximized visibility to the operating site in onedirection versus another. Alternatively, the shaft may be othergeometric configurations depending upon a particular purpose, I-beam,square, polygonal, etc.

It is also envisioned that the end effector assembly 100 is optimizedfor reengaging long tissue sections and visibility of the operatingsite. The jaw members 110 and 120 may also be dimensioned to includedistal ends configured for gross or blunt dissection.

The inclusion of a knife blade in bipolar forceps has been problematicin that it is difficult to provide a knife blade having enoughflexibility to move within a knife slot channel curve while beingresistant to buckling during activation. Further, it has been difficultto design a knife blade that does not add to the overall height of thefront profile of the forceps, and/or is pre-disposed within thestructural jaw of the forceps prior to activation. Moreover, it has beenproblematic to design a knife blade durable enough to cut tissue whilehaving the ability to go around or through the cam pin. It is envisionedthat these design features are now obtainable by providing a knife blade190 having specific parameters in accordance with the presentdisclosure.

Referring now to FIG. 15A, one embodiment of knife blade 190 is shown inaccordance with the present disclosure having proximal end 260, distalend 262, web section 264, and knife rod attachment section 266. Rodattachment section 266 is compatible with an over-molding process forconnecting the knife blade 190 to a blade rod (not shown in FIG. 15A).For example, aperture 268 defined in proximal end 260 is configured tofortify the over-molding process by providing a space where a mold willset when cured. Still referring to FIG. 15A, distal end 262 is shownhaving a slicing angle X. As mentioned above, it is envisioned that theslicing angle X of the tip of the knife blade 190 may be dimensioned toprovide more or less aggressive cutting angles X depending upon aparticular purpose. For example, where an aggressive cutting angle isdesired, angle X may be about 10° to about 30° relative to vertical axisB-B′. In particular embodiments, a suitable slicing angle is about 15°relative to vertical axis B-B′. Also shown in FIG. 15A is slot 272 thatis defined within the web section 264 to provide clearance for pin 139(See FIG. 11) of the drive sleeve 134 (See FIG. 11) during reciprocationof the knife 190. In embodiments, web section 264 has a length of about1.6 inches to about 2.1 inches and an aspect ratio greater than about0.25. In other embodiments, blade 190 has a length of about 3.8 to about4.5 inches along longitudinal axis A-A′ defined therethrough. In stillother embodiments, blade 190 also has a thickness of about 0.008-0.010inches, and blade 190 has a height of about 0.100 inches.

Referring now to FIG. 15B a front perspective view of blade 190 isshown. Distal end 262 is configured to generally converge to form adistal edge 267 having a grind angle, bevel or chamfer 280 shown betweenthe outer portion of distal edge 267 and longitudinal axis A-A′.Suitable angles in accordance with the present disclosure include anglesof about 10° to about 30° relative to the longitudinal central axisA-A′.

Blade 190 may be made of a variety of materials that provide highstrength, and high flexibility. Furthermore, blade 190 may be made ofrazor blade stainless steel (4-40 or 4-20 stainless steel) with athickness of about 0.008 inches to about 0.010 inches. The blade 190 mayalso be made of high carbon steel material such as A-2, O-1, D-2, andDamascus steel, high carbon stainless steel material such as ATS-34,BG-42, S3OV, 154CM, 420HC, and 440C. In particular embodiments, blade190 may be made of surgical stainless steel material such as steelsdesignated as 440-A and 440-B. Blade 190 may also be made of titanium,and ceramic materials such as zirconium oxide. It is further envisionedthat knife blade 190 may be manufactured using a photo-chemical etchingprocess with a machine ground cutting edge. Suitable materials formaking blade 190 through this process, include any of the previouslymentioned materials as well as aluminum, beryllium copper, brass, copperalloys, nickel silver, phosphorous bronze, stainless steel, steel, andcombinations thereof.

As described above, knife rod 193 mounts to the proximal end 260 ofknife 190 via one or more mechanically interfacing elements or affixedin any known manner in the art such as an over-molding process.Referring to FIG. 16, knife rod 193 is shown having a proximal end 330,distal end 332, first longitudinal section 334 containing distal end332, second longitudinal section 338 containing proximal end 330, andthird longitudinal section 336. Blade 190 is connected to the distal end332 of the knife rod 193 (See FIG. 11).

First longitudinal section 334 includes a clocking feature to interactwith the inner workings of the forceps and drive sleeve 134 (See FIG.11) to ensure alignment of the knife rod 193 therein. As used herein,“clocking feature” refers to the ability of a rod to be aligned within alinked mechanism. Accordingly, the clocking feature enables the bladerod to mechanically interface on another component moving adjacent tothe rod such that it rotates or moves in a similar direction. It isenvisioned that the first longitudinal section 334 has a plurality ofedges in order to provide a clock effect. For example, the firstlongitudinal section 334 has a predetermined cross-sectional shape andmay further include a solid or hollow cross-sectional profile. Referringnow to FIGS. 17(A-L) various envisioned front perspectivecross-sectional views of the first longitudinal section 334 are shownhaving a plurality of edges 340. For example, FIG. 17A shows firstlongitudinal section 334 having a multi-sided cross-section having threeedges 340. Moreover, FIG. 17A shows the first longitudinal section 334having a cross-section with triangular dimensions. FIG. 17B shows thefirst longitudinal section 334 having a square cross-section with fourperipheral edges 340. FIG. 17C shows the first longitudinal section 334having a rectangular cross-section. FIG. 17D shows the firstlongitudinal section 334 having a pentagonal cross-section with fiveperipheral edges 340. FIG. 17E shows the first longitudinal section 334having a hexagonal cross-section with six peripheral edges 340. FIG. 17Fshows the first longitudinal section 334 having a heptagonalcross-section with seven peripheral edges 340. FIG. 17G shows the firstlongitudinal section 334 having an octagonal cross-section with eightperipheral edges 340. FIG. 17H shows the first longitudinal section 334having a nonagonal cross-section with nine peripheral edges 340. FIG.17I shows the first longitudinal section 334 having a decagonalcross-section with ten peripheral edges 340.

As shown best in FIGS. 17A-17I, the first longitudinal section 334 orportion of the knife bar may have a solid symmetrical cross-sectionalprofile. Alternatively, as shown best in FIG. 17J it is envisioned thatthe first longitudinal section 334 has a hollow symmetricalcross-section, e.g., the cross-section may include one or morelongitudinal voids 341. FIG. 17K shows the first longitudinal section334 with a substantially round cross-section. The first longitudinalsection 334 may include one or more flange 351 extending from the firstlongitudinal section to allow a substantially circular cross-section forclocking purposes. Flange 351 may extend along the length of firstlongitudinal section 334 and/or extend only a along a portion of thelongitudinal length of the longitudinal section 334 such as flange 352.It is envisioned that the first longitudinal section 334 has a length ofabout 2 to about 5 inches along its longitudinal axis A-A′. Firstlongitudinal section 334 may have a thickness of 0.7 inches to about0.20 inches.

Referring back to FIG. 16, second longitudinal section 338 is made of apredetermined shape and material suitable for interaction with the innerworking components of the forceps device 10. For example, as best seenin FIG. 19 and FIG. 21, the shape of the second longitudinal section maybe suitable for interacting with gears such as toothed or pegged wheelsmeshed together to transmit motion and force from a finger activatedassembly. For example, it is envisioned that the second longitudinalsection is shaped to: form a connection in a bevel gear, form a portionof a gear such as a worm gear or a combination of a gear meshed with thethread, form a toothed rack for a rack and pinion set, or a single gearwhere a pinion meshes with the second longitudinal section to convertrotary motion to back and forth motion. It is also envisioned that thesecond longitudinal section may be an extension of the firstlongitudinal section with no variations in shape. The secondlongitudinal section 338 may have a length of about 1 inch to about 2inches along its longitudinal axis A-A′. In embodiments, secondlongitudinal section may have a thickness of about 0.15 inches to about0.5 inches and particularly 0.160 inches.

Referring to FIG. 16, the knife rod 193 may optionally include a thirdlongitudinal section 336 having a substantially circular cross-section.The third longitudinal section 336 may be narrower than the firstlongitudinal section 334. A tapered portion 350 may also be includedbetween to the first longitudinal section 334 and the third longitudinalsection 336. It is envisioned that the third longitudinal section 336has a length of about 1 inch to about 4 inches along the longitudinalaxis A-A′. In particular embodiments, third longitudinal section mayhave a thickness of about 0.20-0.05 inches.

The inclusion of the trigger assembly described above may be problematicdepending upon the particular manual dexterity of the user. For exampledepending upon the skill and/or preferences of some surgeons, some usersmay find increased manual dexterity when operating an alternative knifeactivating mechanism such as a thumb activator. Accordingly it isdesirable to provide alternative knife activation mechanisms to thetrigger assembly described above. Suitable alternatives to the triggermechanism include various finger activating devices such as a thumbslide cutter with levers, thumb slide with rack and pinion, thumb wheel,thumb wheel with cutter levers, thumb wheel cutter with gears, andcombinations of these mechanisms.

Turning now to FIG. 18, one embodiment of a bipolar forceps 400 is shownfor use with various surgical procedures and generally includes ahousing 420, a handle assembly 430, a knife activating assembly 470suitable for operating end effector assembly 100 that cooperates tograsp, seal and divide large tubular vessels and large vascular tissues.Thumb lever 440 is shown connected to a series of levers 450 incommunication with knife rod 493. When the user pushes distally on thumblever 440 in the direction of arrow 445, the force is transferredthrough the lever 450 into knife rod 493. Consequently the knife rod 493moves distally and actuates the knife (not shown in FIG. 18).Conversely, pulling proximally on the thumb lever 450 will pull onlevers 450 and move knife rod 493 proximally, retracting the knife (notshown in FIG. 18). A spring (not shown) may also be provided that biasesthe knife in a proximal-most position.

Turning now to FIG. 19, another embodiment of a bipolar forceps 500 isshown having a knife activating assembly 570 suitable for operating endeffector assembly 100. Thumb lever 540 is shown shaped with a racksurface 541 connected to a pinion 542 in communication with the secondlongitudinal rack surface 538 of knife rod 593. When the user pulls onthumb lever 540 in the direction of arrow 545, the force is transferredthrough the pinion 542 into the second longitudinal section 538 of kniferod 593. Consequently the knife rod 593 moves distally and actuates theknife (not shown in FIG. 19). Conversely, pushing on the thumb lever 540will rotate piston 542 and move knife rod 593 in a proximal directionand retract the knife (not shown in FIG. 19). A spring (not shown) mayalso be provided that biases the knife in a proximal-most position.

Turning now to FIG. 20, another embodiment of a bipolar forceps 600 isshown having a knife activating assembly 670 suitable for operating endeffector assembly 100. Thumb wheel 640 is shown shaped with a flange 641inside the housing 620. Flange 641 is connected to a rod 642 and aseries of one or more levers 643 that are in communication with kniferod 693. When the user pulls on thumb wheel 640 in the direction ofarrow 645, the force is transferred through flange 641, rod 642, levers643 and knife rod 693. Consequently the knife rod 693 moves distally andactuates the knife (not shown in FIG. 19). Conversely, pushing the thumbwheel 650 distally will rotate flange 641 proximally and pull levers 643and knife rod 693 in a proximal direction. Consequently, the knife rod693 moves proximally and retracts the knife (not shown in FIG. 20).

FIG. 21 shows another embodiment of a bipolar forceps 700 is shownhaving a knife activating assembly 770 suitable for operating endeffector assembly 100. Thumb wheel 740 is shown shaped with a circularrack 742 inside the housing 720. Rack 742 is connected to a gear 743which is in turn connected to the second longitudinal rack section 738of the knife bar 793. When the user moves thumb wheel 740 in thedirection of arrow 645, the force is transferred through rack 742, gear743, and knife rod 793. Consequently the knife rod 793 moves distallyand actuates the knife (not shown in FIG. 19). Conversely, moving thethumb wheel 740 opposite arrow 645 will rotate gear 743 and pull kniferod 793 in a proximal direction, and retract the knife (not shown inFIG. 21).

While several embodiments of the disclosure have been shown in thedrawings, it is not intended that the disclosure be limited thereto, asit is intended that the disclosure be as broad in scope as the art willallow and that the specification be read likewise. Therefore, the abovedescription should not be construed as limiting, but merely asexemplifications of particular embodiments. Those skilled in the artwill envision other modifications within the scope and spirit of theclaims appended hereto.

What is claimed:
 1. A bipolar forceps, comprising: a housing; a shaftaffixed to the housing having jaw members at a distal end thereof; adrive assembly that moves the jaw members relative to one another from afirst position wherein the jaw members are disposed in spaced relationrelative to one another to a second position wherein the jaw members arecloser to one another for manipulating tissue; a movable handlerotatable about a pivot to force the drive assembly to move the jawmembers between the first and second positions; a knife assembly havinga movable knife rod that translates a knife blade between the jawmembers when the jaw members are disposed in the second position; and aknife activating assembly in communication with the knife rod andconfigured to translate the knife blade upon actuation thereof, theknife activating assembly including first, second and third levers, thefirst lever actuatable by a user, the third lever in communication withthe knife rod, and the second lever being the intermediary levertherebetween, wherein the second and third levers are pivotally coupledto the knife rod.
 2. The forceps according to claim 1, wherein the firstlever is a thumb lever.
 3. The forceps according to claim 2, wherein aportion of the thumb lever is disposed exterior of the housing.
 4. Theforceps according to claim 2, wherein, when a force is applied to thethumb lever, the knife rod moves distally to actuate the knife blade. 5.The forceps according to claim 1, wherein the first lever issubstantially parallel with respect to the knife rod.
 6. The forcepsaccording to claim 1, wherein the second and third levers form asubstantially inverted V-shaped configuration.
 7. The forceps accordingto claim 1, wherein a length of the second lever is equal to a length ofthe third lever.
 8. The forceps according to claim 7, wherein a lengthof the first lever is greater than the lengths of the second and thirdlevers.